Mysql – pt-query-digest slowlog output format looses query cache hit information

MySQLpercona-toolkitperformancequery-cacheslow-log

I'm using pt-query-digest (v2.2.20) slowlog output format to filter out queries based on their timestamp, to run further digests on the filtered slowlog :

ptqd 11-21.slow.log --output slowlog --no-report --filter '($event->{timestamp} > 1483957800) && ($event->{timestamp} < 1483959600)' > 11-21.halfhour.log

The point is my source log 11-21.slow.log has query cache hit info, for instance :

# Time: 170109 12:08:43
# User@Host: pidf_user[pidf_user] @ [10.226.13.132]
# Thread_id: 32829731 Schema: webmbpidf QC_hit: No
# Query_time: 0.015387 Lock_time: 0.000038 Rows_sent: 0 Rows_examined: 0

Whereas the filtered output 11-21.halfhour.log doesn't :

# Time: 170109 11:59:59
# User@Host: pest_user[pest_user] @ 10.226.13.13 []
# Thread_id: 32805954
# Query_time: 0.000221 Lock_time: 0.000000 Rows_sent: 0 Rows_examined: 0

l lose schema information as well but it's less a problem in my situation.

Is there a way to keep the query cache info in the slowlog output ?

Any help would me much appreciated.

Best Answer

It appears to be a known bug that's already been reported since 2013.

So the actual answer to my question is no: by now it's impossible not to loose this information when outputting a slowlog with pt-query-digest.

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